Honestly I don't know which study you're talking about, and I'm not trying to question what you're saying (such studies indeed often use exaggerated amounts because it's more likely to show effects, but it can skew the results of course) but I just found it interesting that depending on what "feeding them coffee in the amount of 3/4 of their body weight" means, well over a pregnancy it's easy to consume 3/4 of one's body weight in coffee.
It means about 150 mL coffee per day for a woman weighing 55 kg, over 9 months.
About SIDS and sleeping with the children in the same bed, if I remember correctly (it's been some time since I had to read about this) the very large majority of cases happened with parents who either smoke or are obese. I think I couldn't find precise stats just for non-smoking, non-obese parents but it seems like SIDS basically didn't happen in this case when co-sleeping. It also almost never happens with immigrant parents for some reason (even though they are statistically more likely to practice co-sleeping, here in Europe).
You absolutely don't have awareness of everything nearby when you're asleep. You are inherently incapable of even determining this because you're sleeping. I'm sure you react to some stimuli but that doesn't mean you can expect yourself to react to every potential stimuli that you would want to.
I would obviously suggest to be very honest with yourself, but if you are a light sleeper and don't roll (we didn't), the most you have to be careful of is heat. Otherwise, enjoy the cuddly night